Process for cladding metals and the product thereof



jan. 13, 1942. s, DEUTSCH 2,269,523

PROCESS FOR CLADDING METALS AND THE PRODUCT THEREOF Filed April 8, 1939 f gyra W V// D y MW m,

fw sf Afro/Nays Patented Jan. 13,1942

PROCESS FOR CLADDING METALS AND THE PRODUCT THEREOF Siegfried Deutsch, Brussels, Belgium, assigner to Ellis Miller, Brussels, Belgium Austria. May 31, 1937 Applicatolr April 8, 1939, Serial No. 266,865

` 26 Claims.

This invention relates to the plating of metal bodies such as ships plates, sheet metal for the manufacture of containers and utensils, for the manufacture of shells or coverings for bullets and for like purposes.

In its broadest aspects, the present invention relates to the cladding of a `body of metal with a superposed body of a rcladding metal,A` with an intermediate sheet or layer of a high cuprous content metal, the base metal and the cladding metal being bonded together by diffusion of the intermediate layer. More specifically, the process relates to the making of a stainless-clad steel in whichfa body of plain steel is rst electroplated with nickel and then with copper or a cuprous metal, the stainless steel, which is to form the cladding body, being then electroplated with a cuprous metal, and the two plated bodies superimposed one upon the other, with their cuprous faces contiguous, the stack so formed being then heated under heavy pressure at a temperature suiiicient to cause the plating metals to form a diffusion bond between the stainless and plain steel bodies. In a modied form of the invention, a copper-clad steel is produced in which the plain steel is rst electroplated with nickel and then with a cuprous metal, or the plain steel is directly electrplated with the cuprous metal, a sheet of copper being similarly plated and then superimposed upon the body of plain steel, the stack so formed being heated under heavy' pressure and at a temperature suiiciently high to` cause the plating metals to form a diffusion bond between the plain steel and the copper-cladding body.

It has already been proposed to cover metal bodies, such as those of iron, with layers of rustless steel (chromium-nickely steel) by applying a coating of nickel, or nickel alloy, to the one surface of a thin sheet of such steel, said sheet being then laid with the nickel-coated side downward, on the body to be clad, and the packthen subjected to pressure in a furnace at a high temperature. The object of such treatment is to cause 'the layer of nickel, or nickel alloy, to unite the two metals, between which it is located, by forming an alloy by diiusion, and thus establish, between the metal body and the cladding sheet, a mechanical union sufticiently strong tol enable the clad metal body to be subjected to mechanical treatment, such as rolling, drawing, bending and the like in the hot or cold state, without the cladding sheet becoming detached therefrom.. However, if the said alloy is to be formed by diffusion, a very high temperature is necessary an (ci. 2er-189) since some chromium-nickel steels, when heated to high temperatures, undergo such chemical and l physical changes that their capacity to resist acids and rusting is more or less impaired, the said process is inapplicable for cladding a metal body with a covering of rustor acid-proof steel.

According to the present invention, the cladding process, which the pack, comprising the metal body and the cladding sheet, is heated under heavy pressure, is carried out by employing copper as the coating material for the formation of the uniting layer. If, however, the materials .composing the metal bodyand the cladding sheet are liable to suier damage, through being penetrated Aby the copper, when heated under pres-l sure, there is provided between thecopper coating and said materials, a coating of a metal or metal alloy, which protects the material of the parts to be united against the injurious influence of thecopper, and is adapted to form-by diffusion with said materials and with the copper, when heated under pressure, an alloy capable of withstanding subsequent deformation treatment, such alloy being formed at a temperature which does not injure the mechanical and physical properties of the parts to be united.

In cladding an iron body with chromium (rustless) steel, the two parts may be provided, according to the invention, first with a coating, preferably by electroplating, of v nickel, or other metal with similar properties, and with a coating of copper. If the two parts are then superimposed, so that the coatings of copper are in contact, and the pack is heated under pressure, a considerably lower temperature than when a simple intermediate layer of nickel is employed,

will suflice to effect the union of the two layers of copper, and also the formation of alloys by diiiusion-at least at the boundaries between copper and nickel. If-as is the case when an electroplated coating of nickel is concerned-the nickel coating already adheres firmly, both to the metal body, which may be iron plate, and the cladding sheet, the intermediate layer, consisting of copper, or copper-nickel alloy, ensures such a rm union between the cladding sheet and the metal body, that it becomes directly possible to subject the compound body to all kinds of mechanical treatment, both in the cold and hot condition. Despite such mechanical treatments, the union of th'e parts is maintained, because the intermediate layer has a higher ductility than iron and steel, or than an iron-nickel alloy. 4

, In any event, however, the temperature required for the formation of the diffusion alloy between copper and nickel is so low that it cannot impair the properties of the steel sheet. For example, with heavy pressure heating at about 1000" C. for some 2-3 hours is sufficient.

Heating under corresponding heavy pressure can also be applied in the case of packs consisting of a plurality of metal bodies with cladding sheets in the known manner. Plating sheets mayI be applied to one or both sides of the metal body.

Various metals can be employed, both for the met-al body and the plating sheets. In any event, however, owing to the fact that a copper coating is provided over the nickel coating, the temperature required for the formation of the alloy by diffusion is lower than would be needed to form such an alloy between nickel and iron. The process is therefore also advantageous in cases when no risk must be incurred of the metals employed suffering damage through excessive heating as the diffusion is formed -at a relatively low temperature, (under 1000 C.).

An advantage of the original work being thin is that thin sheets which are intended to be superimposed and heated under pressure, for cladding purposes, can be more easily pressed tightly together than is the case with thicker sheets. The surfaces of the sheets which are to be united are never absolutely even, but thin sheets fit together more easily under pressure than thick sheets, and the union produced by means of the alloy formed by diffusion is therefore more uniform and stronger.

The layers of nickel and copper should be as thin as possible, as compared with the thickness of the metal body and of the plating sheet. In the case of iron or steel, the presence of an intermediate layer of nickel between the copper and the iron, or steel, has the advantage of preventing the penetration of copper into the iron, or iron alloy, and the resulting adverse inuence on the properties of said metals.

In place of nickel, other metals (such as silver) with similar properties may be used as the first coating material for the two pieces of work to be united.

If an iron body is to be clad with copper, nickel, or their alloys, the said body can be provided with a thin coating of brass, red brass or the like,

whilst the plating sheet is given a thin coating of alloys of copper and tin, or copper and zinc. If the plating metal has a high copper content, this latter metal may be omitted entirely from the intermediate layer, and consequently, there is no need to apply any coating, at all, to the cladding sheet.

When, owing to the properties of the materials employed, or to the thickness of the metal body, or of the plating sheet or sheets, Iconsiderable differences in ductility between the metal body and the plating sheet are to be expected during rolling or drawing, Without disruption of the intermediate bonding layer.

Conditions of this kind arise, for example when an iron or steel plate with a thickness of about 30 mm. is plated with a sheet of chromium steel about`3 mm. thick, and this work is to be sub- Jected to various deformation treatments. -In such an event, coating the metal body and cladding sheet, to be superimposed, with a thin electrodeposited coating of nickel, and of copper respectively only. a few thousandths of a millimetre thick, is not sumcient to produce, when heated under pressure, an intermediate layer of diffusion alloy capable of absorbing the stresses set up through the difference in the ductility of such workpieces, in the operation of rolling. In the case of a thick metal body and a thick plating sheet, i. e. heavy plating, the intermediate layer I lar to the thickness, to occurwithout destroys ing the intermediatelayer-during rolling, drawing or other deformation treatment, as the result of the different elongation-due to the thiclmessof the metal body andcladding sheet.

In order to obtain such thick intermediate layers, a correspondingly heavy galvanic deposit could be provided. In some cases, however, the intermediate layer mustvbe very thick if it is to conform with the aforesaid conditions, for example, inthe case where a metal body 30 mm. thick is to be clad with a chromium steel sheet 3 mm. thick. In such a case, the intermediate layer must have a thickness of about 1 mm., since experience has shown that the thickness of the intermediate layer should be about one-third that of theplating sheet. Electroplated coatings for the formation of an intermediate layer of the prescribed thickness would, however, be uneconomical, apart from the diiliculties attending their production.

According to the invention, the. coatings applied to the metal body and cladding sheet are of the usual thickness only, but, prior to the heating under pressure, there is laid, between the superimposed surfaces of said body and sheet, a copper plate, adapted to form a diffusion alloy with the coatings, whilst also possessing the requisite mechanical properties and being so dimensioned as to form, in conjunction with the coatings, a layer of such a thickness as is needed, for technical reasons, to produce 'a union capable of withstanding any deformation treatment of the work. Materials highly suitable for the intermediate sheet are: copper-zinc alloys (red-brass, brass, or the like), or silver-copper alloys. example above mentioned, the metal body be provided with a nickel and copper coating, 0.015 mm. and 0.030 mm. respectively, and the cladding sheet with a nickel and copper coating, 0.005 mm. and 0.015 mm. respectively, an intermediate sheet of red brass, about 0.8 mm. thick. may be used.

In the case of work intended to be annealed, the intermediate layer must be soV constituted as to withstand the annealing temperature, and the intermediate sheet must therefore have a melting point of at least l0001040 C.

The invention is illustrated by the diagrammatic drawing, wherein Fig. 1 is a cross section of a pack constituted of a body to be plated and having a plurality of layers of materials superposed thereon prior to subjecting the pack to heat and pressure; Fig. 2 shows, in section, a plurality of packs within the platens of a press;

If, in the and Fig. 3 is a similar view, but of differently constituted packs of body and plating material.

Referring more particularly to the drawing:

In Figure 1'a represents a mild steel body to be plated, b a protective layer of nickel applied galvanically to thebody a, c a layer of copper applied galvanically to the layer b, d a sheet of rustless steel with which the body ais to be plated, e a protective layer of nickel applied galvanically to the sheet d, and f a layer of copper applied galvanically to the layer e. The sheet d is superposed on the body a with the layer e contiguous with the layer c and the pack so formed is subjected to heat and heavy pressure.

Figure 2 shows a plurality of bodies a, with plating sheets d, on opposite sides of each body a, each pack d, e, f, c, b, a, being separated from the adjacent pack by a layer g of insulating material and the assemblage of packs located between the head h and base i -of a press.

Figure 3 shows an assemblage of packs similar to that shown in Figure 2, but in this case k is a soft-steel body, m-is a protective layer of nickel applied galvanically to the body k, n isa layer of copper applied galvanically to the layer m and o is a plating sheet which contains more than 50% of copper.

The heating of the metal pack is carried out in known manner in a suitable furnace, the usual precautions being employed to prevent oxidation of the metal surfaces, as by conducting the heating in a more or less evacuated space or in a space lled with an inert atmosphere or by welding or otherwise protecting the' free edges of the superposed metal layers, or otherwise.

I claim:

1. The 'process of making a'composite metal cladded body which comprises plating the surface of a base metal sheet with nickel, plating the surface of a cladding metal sheet with nickel, superposing a layer of va high copper content metal upon the nickel plated' surfaces of both the base and cladding sheets, superposing said base and cladding sheets with their copper surfaces contiguous, and heating under heavy diffusion pressure the pack so formed at a temperature suiiiciently high to cause the plating metals to form a diffusion bond between the base sheet and the cladding sheet.

2. The process of making a composite metal cladded body which comprises plating the surface of a base metal sheet with nickel, plating the surface of a cladding metal sheet with nickel, superposing a layer of copper upon the nickel plated surfaces of both the base and cladding sheets, superposing said base and cladding sheets with their copper surfaces contiguous, and heating under -heavy diffusion pressure the pack so formed at a temperature sufficiently high to cause the plating metals to form a diffusion bond between the base sheet and the cladding sheet.

3. The process of making a composite metal cladded body which comprises plating the surface of a base metal sheet with nickel, plating the surfaceof a cladding metal sheet with nickel,

Iii

face of a base metal sheet with nickel, plating the surface of a cladding metal sheet with nickel, plating a layer of a high copper content metal upon the nickel plated surfaces 'of both the base and cladding sheets, superposing said base vand cladding sheets with their copper.v surfaces contiguous, and heating under heavy diffusion pressure the pack so formed at a temperature suiliciently high to cause the plating metals to form a'diifusion bond between the base sheet and the cladding sheet.

5. The process of making a composite metal cladded body which comprises plating the surface of a base metal sheet with nickel, plating the surface of a cladding metal sheet with nickel,

l cladded body which comprises plating the surface of a base metal sheet with nickel, plating the surface of a cladding metal sheet with nickel, superposing a layer of copper upon the nickel plated surfaces of both the base and cladding sheets, .superposing said base 'and cladding sheets with their copper surfacescontiguous, and heating at a temperature at least 50 C. below the melting point of the cladding metal, and under plating metals to form a diffusion bond between the base sheet andthe cladding sheet. l

7. The process of making a stainless-clad steel` which comprises plating the surface of a body of plain steel with nickel, plating the surface of a -body of stainless steel with nickel, superposing upon the nickel plated faces of said two bodies a layer of metal of high copper content, superposing said bodies with their cuprous surfaces contiguous and heating under heavy diffusion pressure the pack so formed at a temperature suilciently high to cause the plating metals to form va 'diffusion bond between the stainless and plain steel bodies.

8. The process of making a stainless-clad steel which comprises plating the surface of a body of plain steel with nickel, plating the surface of a body of stainless steel with nickel, superposing upon the nickel plated faces of said two bodies a layer of copper, superposing said bodies with their copper surfaces contiguous, and heating under heavy diffusion pressure the pack 'so formed at a temperature sulciently high to cause the plating metals to form a diffusion bond between the stainless and plain steel bodies.

9. The process of makingv a stainless-clad steel which comprises plating the surface of a body of plain steel with nickel, plating the surface of a body of stainless steel with nickel, plating the plating a layer ofA copper upon the nickel plated surfaces of both the base and cladding sheets, superposing said base and cladding sheetswith their copper surfaces contiguous, and, heating under heavy diffusion pressure the pack so formed at a temperature suiliciently high to cause the plating metals to form a diffusion bond between the base sheet and the cladding sheet. l

4. The process of making a composite metal cladded body which comprises plating the 'sursuiciently high to cause the plating metals to cause a diffusion bond between the stainless and plated steel bodies.

10. The process of making a stainless-clad steel which comprises plating the surface of a body of plain steel with nickel, plating the surface of a body of stainless steel with nickel. plating the nickel plated faces of said two bodies with a layer of copper, superposing said bodies with their copper surfaces contiguous, and `heating under heavy diffusion pressure the pack so formed at a temperature sufficiently high to cause the plating-metals to form a diffusion bond between the stainless and plain steel bodies.

11. The process of making a stainless-clad steel which comprises plating the surface of a body l which comprises plating the surface of a body` of plain steel with nickel, plating the surface of a body of stainless steel with nickel, superposing upon the nickel plated faces of said two bodies a layer of copper, superposing said bodies Awith their copper surfaces contiguous, and heating at a temperature at least C. below the I melting point of the cladding metal and under heavy pressure the pack so formed to cause the plating metals to form a diffusion bond between the stainless and plain steel bodies.

13. 'I'he process of making a stainless-clad steel, which comprises superposing a layer of metal of high copper content upon a body of plain steel, plating the Asurface of a body of stainless steel with nickel. superposinga layer of metal of high copper content upon the nickel Vplated face of said body of stainless steel, forming a pack of Said plain Steel and stainless Steel bodies:

with their cuprous surfaces contiguous, and heating under heavy diifusion pressure the packyso formed, at a temperature suillciently high to cause the plating -nickel and cuprous metal to form a diifusion bond between the stainless and plain steel bodies. Y

14. The process of making a copper-clad steel which comprises plating the surface of a body of plain steel with nickel. superposing a layer of a high copper-content metal upon the nickel surface, and heating under heavy diffusion pressure the laminated sheet so formed at a temperature sumciently high to cause the cuprous layer to diffuse into the protective nickel layer and the latterinturntodiifuseintothesteelbody.

15. The process of making a copper-clad steel which comprises plating the surface of a body of plain steel with nickel, superposing a layer of copper upon the nickel surface, and heating under heavy diffusion pressure the laminated sheet so formed at a temperature sufficiently high to cause the cuprous layer to diffuse into the protectlve nickel layer and the latter in turn to dif.

fuse into the steel body.

16. The process of making a copper-clad steel which comprises plating the surface of a body of plain steel'with nickel, superposing a layer of a high copper-content metal upon the nickel surface, and heating at a temperature of about 1000u C.. and under heavy pressure the laminated sheet so formed to cause the cuprous layer to diffuse into the protective nickel layer and the latter inturntodilfuseinto thesteelbody.

1'7. A process for making a composite metalcladded body, in which the process of plating with nickel and a layer of a high cuprous content metal as set forth in claim l is duplicated on both sides of the base metal sheet.

18. A process for making a stainless-clad steel, in which the process of plating with nickel and a layer of a high cuprous-content metal as set forth in claim 7 is duplicated on both sides of the body of plain steel and at least one side of the body of stainless steel.

19. The process of making a composite metal cladded body which comprises plating the sur face of a base metal sheet with a thin layer of a metal which will readily diffuse into the metal of the base sheet, superposing a layer of a high copper content metal upon said plating layer, the intermediate plating layer constituting a protective material against the influence of the copper upon the'base sheet and forming, by diffusion with the base sheet metal and with the copper, when heated under heavy pressure, an alloy capable of withstanding subsequent deformation treatment, plating the surface of another metal sheet, constituting the cladding material. with a thin layer of the same protective metal and then with a high copper content metal. superposing said sheets with their copper surfaces contiguous. and heating under heavy pressure, at a temperature which will not have an effect of altering the mechanical and physical properties of the parts to be united. the pack so formed, to cause the copper layers to form a diffusion bond between the base metal sheet and the cladding metal sheet.

20. The process of making a stainless-clad steel which comprises plating the surface of a body forming, by diffusion with the plain steel and' with the copper, when heated under heavy pressure, an alloy capable of withstanding subsequent deformation treatment, plating the surface of a body of stainless steel, constituting the cladding material, with a thin layer of the same protective vmetal and then with a high copper content metal, .superposing said bodies with their copper surfaces contiguous, and heating under heavy pressure, at a temperature which will not have an eifect of altering the mechanical and physical properties of the parts to be united, the pack so formed, to cause the copper layers to form a diffusion bond between the plain steel and the cladding stainless-steel.

21. The process of making a copper-clad steel which comprises plating the surface of a body of plain steel with 'a thin layer of a metal which will readilydiffuse into the plain steel, superposinga layer of a high copper content metal upon said plating layer, the intermediate plating layer constituting a protective material against the inuence of the copper upon the plain steel and forming, by diiusion with the plain steel and with the copper, when heated under heavy pressure, an alloy capable of withstanding subsequent deformation treatment and heating under pressure,

ing a baseof ferrous metal. a surface plating of electrodeposited nickel, and an electrodeposited layer of copper, upon. said plating of nickel'. the

cupi-ous layer being diiiused into the nickel and the-nickel in tum being diiused into the base oi'A .5

ferrous metal.

23. A composite metal cladded b0dycompris ing a base of ferrous metal, a surface plating of electrodeposited nickel upon said base. an electrodeposited layer of copper upon said plating of l0 nickel, a superposedlayer of a high copper content metal upon the electrodeposited layer of copper and a cladding metal sheet of high cuprous' content having an electrodeposited layer of copv per on the surface thereof in contact with said l5 superposed layer of copper.

24. A composite metal cladded body compris-rr 'v ing a base of ferrous metal, a surface plating of electrodeposited nickel upon said base, an electrodeposited layer of copper upon said plating oi V2l) nickel and a cladding metal sheet of high cuprous 25. A stainless-clad. steel block comprising aA base of plain steel, a surface plating of nickel, a -layer of metal of high cuprous content upon said plating of nickel, a sheet of stainless steel similarly plated on one face with nickel and a plated layer of metal of high cuprous content upon said plating of nickelrtheplated stainless steel sheet being in juxtaposition with the plated plain steel,

' with"the cuprous surfaces thereof contiguous,

and the plating metals constituting a diffusion bond between the stainless and plain steel bodies.

26. A stainless-clad steel block comprising a base of plain steel, a surfaceplating of nickel, a

- layer of copper upon said plating of nickel, a

sheet of stainless steel similarly plated on one -face with nickel and a plated layer of copper` upon said plating of nickel, the plated stainless steel sheet being in juxtaposition with the plated plainjsteel, with the cuprous surfaces thereof contiguous, and the plating metals constituting 'a diil'usion bond between the stainless and plain Steel bodies.

A SIEGFRIED DEUTSCH. 

